A report released by the Centers for Disease Control and Prevention found that tobacco use in the most popular films hit a high in 2005, and has been falling since.

According to the analysis, fewer than half of 2009’s top releases showed smoking. That was a record low for the 1991-2009 period covered by the researchers.

The study’s authors believe that the more smoking children and teens see in movies, the more likely they are to pick up the habit.

Since 2007, the Motion Picture Association of America has considered the amount of smoking in its ratings system.

Some safety groups, including Smoke Free Movies and SceneSmoking.org, are pushing for an R rating for any movies that include smoking.